Case fatality rate

Case Fatality Rate (CFR)

The Case Fatality Rate (CFR) is a measure used in epidemiology to determine the severity of a disease. It represents the proportion of individuals diagnosed with a particular disease who die from that disease within a specified period. The CFR is typically expressed as a percentage and is calculated using the following formula:

<math> \text{CFR} = \left( \frac{\text{Number of deaths from the disease}}{\text{Number of diagnosed cases of the disease}} \right) \times 100 \% </math>

Calculation

To calculate the CFR, accurate data on both the number of diagnosed cases and the number of deaths caused by the disease are required. The formula is straightforward:

<math> \text{CFR} = \left( \frac{D}{N} \right) \times 100 \% </math>

where:

• D is the number of deaths due to the disease.
• N is the number of diagnosed cases of the disease.

Importance

The CFR is an important metric in public health and epidemiology because it helps to assess the lethality of a disease. It is particularly useful during outbreaks and epidemics to understand the impact of the disease on the affected population. A high CFR indicates a more lethal disease, while a low CFR suggests a less severe disease.

Factors Affecting CFR

Several factors can influence the CFR, including:

• Age and comorbidities of the affected population.
• Healthcare quality and accessibility.
• Virulence of the pathogen.
• Timeliness and effectiveness of medical interventions.

Comparison with Mortality Rate

The CFR should not be confused with the mortality rate, which measures the number of deaths in a given population over a specific period. While the CFR focuses on the proportion of deaths among diagnosed cases, the mortality rate considers the entire population, including those not diagnosed with the disease.

Examples

• During the COVID-19 pandemic, the CFR varied significantly across different regions and age groups.
• The Ebola virus disease has a high CFR, often exceeding 50%.

Limitations

The CFR has limitations, particularly during the early stages of an outbreak when data may be incomplete or inaccurate. Underreporting of cases or deaths can lead to an inaccurate CFR. Additionally, the CFR does not account for the duration of the disease or the time lag between diagnosis and death.

Related Pages

• Epidemiology
• Mortality rate
• Infectious disease
• Outbreak
• Pandemic
• Public health

See Also

• Incidence (epidemiology)
• Prevalence
• Survival rate
• Virulence